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PureKit PHP SDK allows developers to protect users' passwords and sensitive personal information in a database from data breaches and both online and offline attacks and make stolen passwords useless even if a database is breached.
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Virgil PureKit PHP SDK

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Introduction | Features | Register Your Account | Install and configure SDK | Prepare Your Database | Usage Examples | Docs | Support


Virgil Security introduces an implementation of the Password-Hardened Encryption (PHE) protocol – a powerful and revolutionary cryptographic technology that provides stronger and more modern security, that secures users' data and lessens the security risks associated with weak passwords.

Virgil PureKit allows developers interacts with Virgil PHE Service to protect users' passwords and sensitive personal identifiable information (PII data) in a database from offline/online attacks and makes stolen passwords/data useless if your database has been compromised. Neither Virgil nor attackers know anything about users' passwords/data.

This technology can be used within any database or login system that uses a password, so it’s accessible for a company of any industry or size.

Authors of the PHE protocol: Russell W. F. Lai, Christoph Egger, Manuel Reinert, Sherman S. M. Chow, Matteo Maffei and Dominique Schroder.


  • Zero knowledge of users' passwords
  • Passwords & data protection from online attacks
  • Passwords & data protection from offline attacks
  • Instant invalidation of stolen database
  • User data encryption with a personal key

Register Your Account

Before starting practicing with the SDK and usage examples make sure that:

  • you have a registered Virgil Account at Virgil Dashboard
  • you created PURE Application
  • and you got your PureKit application's credentials such as: APP_TOKEN, APP_SECRET_KEY, SERVICE_PUBLIC_KEY

Install and Configure PureKit

The PureKit is provided as a package named virgil/purekit. The package is distributed via Composer. The package is available for PHP version 7.2.

Install PureKit Package

  • Step #1. Add the vsce_phe_php extension into your server before using the PureKit. Read more here.

  • Step #2. Install PureKit library with the following code:

    composer require virgil/purekit

Configure PureKit

PureKit configuration .env file:

UPDATE_TOKEN= //must be empty

Here is an example of how to specify your credentials Protocol class instance:

use Dotenv\Dotenv;
use Virgil\PureKit\Protocol\Protocol;
use Virgil\PureKit\Protocol\ProtocolContext;

// Add correct path to .env file!
(new Dotenv("{PATH_TO_FILE}"))->load();

try {
    $context = (new ProtocolContext)->create([
        'appToken' => $_ENV['APP_TOKEN'],
        'appSecretKey' => $_ENV['APP_SECRET_KEY'],
        'servicePublicKey' => $_ENV['SERVICE_PUBLIC_KEY'],
        'updateToken' => $_ENV['UPDATE_TOKEN']

    $protocol = new Protocol($context);
catch(\Exception $e) {
    // Add your custom logic here

Prepare Your Database

PureKit allows you to easily perform all the necessary operations to create, verify and rotate (update) user's PureRecord.

Pure Record - a user's password that is protected with our PureKit technology. Pure record contains a version, client & server random salts and two values obtained during execution of the PHE protocol.

In order to create and work with user's Pure record you have to set up your database with an additional column.

The column must have the following parameters:

Parameters Type Size (bytes) Description
record bytearray 210 A unique record, namely a user's protected Pure Record.

Usage Examples

You can find out working sample for the following commands in this directory

Enroll User Record

Use this flow to create a PureRecord in your DB for a user.

Remember, if you already have a database with user passwords, you don't have to wait until a user logs in into your system to implement PHE technology. You can go through your database and enroll (create) a user's Pure Record at any time.

So, in order to create a Pure Record for a new database or available one, go through the following operations:

  • Take a user's password (or its hash or whatever you use) and pass it into the EnrollAccount function in a PureKit on your Server side.
  • PureKit will send a request to PureKit service to get enrollment.
  • Then, PureKit will create a user's Pure Record. You need to store this unique user's Pure Record in your database in associated column.
try {
    $enroll = $protocol->enrollAccount($password)); // [record, encryption key]
    $record = $enroll[0]; //save Pure Record to database
    $encryptionKey = $enroll[1]; //use encryption key for protecting user data
catch(\Exception $e) {
    // Add your custom logic here

When you've created a Pure record for all users in your DB, you can delete the unnecessary column where user passwords were previously stored.

Verify User Record

Use this flow when a user already has his or her own Pure record in your database. This function allows you to verify user's password with the Pure record from your DB every time when the user signs in. You have to pass his or her Pure record from your DB into the VerifyPassword function:

try {
    $encryptionKey = $protocol->verifyPassword($password, $record)); //use encryption key for decrypting user data
catch(\Exception $e) {
    // Login error (incorrect password)
    // Login success

Encrypt user data in your database

Not only user's password is a sensitive data. In this flow we will help you to protect any Personally identifiable information (PII) in your database.

PII is a data that could potentially identify a specific individual, and PII can be sensitive. Sensitive PII is information which, when disclosed, could result in harm to the individual whose privacy has been breached. Sensitive PII should therefore be encrypted in transit and when data is at rest. Such information includes biometric information, medical information, personally identifiable financial information (PIFI) and unique identifiers such as passport or Social Security numbers.

PureKit service allows you to protect user's PII (personal data) with a user's encryptionKey that is obtained from EnrollAccount or VerifyPassword functions. The encryptionKey will be the same for both functions.

In addition, this key is unique to a particular user and won't be changed even after rotating (updating) the user's PureRecord. The encryptionKey will be updated after user changes own password.

Here is an example of data encryption/decryption with an encryptionKey:

use Virgil\PureKit\Core\PHE;

try {
    //key is obtained from protocol->enrollAccount() or protocol->verifyPassword() calls
    $data = "Personal data";

    $phe = new PHE();
    $cipherText = $phe->encrypt($data, $encryptionKey);
    $decrypted = $phe->decrypt($cipherText, $encryptionKey);

    // var_dump($decrypted);
catch(\Exception $e) {
    // Add your custom logic here

Encryption is performed using AES256-GCM with key & nonce derived from the user's encryptionKey using HKDF and random 256-bit salt.

Virgil Security has Zero knowledge about a user's encryptionKey, because the key is calculated every time when you execute EnrollAccount or VerifyPassword functions at your server side.

Rotate app keys and user PureRecord

There can never be enough security, so you should rotate your sensitive data regularly (about once a week). Use this flow to get an UPDATE_TOKEN for updating user's PureRecord in your database and to get a new APP_SECRET_KEY and SERVICE_PUBLIC_KEY of a specific application.

Also, use this flow in case your database has been COMPROMISED!

This action doesn't require to create an additional table or to modify scheme of existing table. When a user needs to change his or her own password, use the EnrollAccount function to replace user's oldRecord in your DB with a newRecord.

There is how it works:

Step 1. Get your UPDATE_TOKEN

Navigate to Virgil Dashboard, open your pure application panel and press "Show update token" button to get the UPDATE_TOKEN.

Step 2. Initialize PureKit with the UPDATE_TOKEN Move to PureKit configuration .env file and specify your UPDATE_TOKEN:

UPDATE_TOKEN= //need to be filled

Step 3. Start migration. Use the RecordUpdater::update() PureKit method to create a user's new Pure record (you don't need to ask your users to create a new password). The RecordUpdater::update() method requires the UPDATE_TOKEN and user's old Pure record from your DB:

use Virgil\PureKit\Protocol\RecordUpdater;

try {
    $recordUpdater = new RecordUpdater($_ENV["UPDATE_TOKEN"]);

    $newRecord = $recordUpdater->update($oldRecord));

    // $newRecord is null ONLY if $oldRecord is already updated
    if ($newRecord !== null)
        // Save new record to the database
catch(\Exception $e) {
    // Add your custom logic here

So, run the RecordUpdater::update() method and save user's new Pure record into your database.

Since the PureKit is able to work simultaneously with two versions of user's PureRecords (new Pure record and old Pure record), this will not affect the backend or users. This means, if a user logs into your system when you do the migration, the Virgil PureKit will verify his password without any problems because PureKit can work with both user's Pure Records (new and old).

Step 4. Get a new APP_SECRET_KEY and SERVICE_PUBLIC_KEY of a specific application

Use Virgil CLI update-keys command and your UPDATE_TOKEN to update the APP_SECRET_KEY and SERVICE_PUBLIC_KEY:

// FreeBSD / Linux / Mac OS
./virgil pure update-keys <service_public_key> <app_secret_key> <update_token>

// Windows OS
virgil pure update-keys <service_public_key> <app_secret_key> <update_token>

Step 5. Move to PureKit configuration .env file and replace your previous APP_SECRET_KEY, SERVICE_PUBLIC_KEY with a new one (APP_TOKEN will be the same). Delete previous APP_SECRET_KEY, SERVICE_PUBLIC_KEY and UPDATE_TOKEN.

UPDATE_TOKEN= //must be empty

Additional information

Add the vsce_phe_php extension

  • Download, unzip and execute on your server virgil-test.php file.

  • Download and unzip vsce_phe_php extension according to your server operating system.

  • Make sure you have access to edit the php.ini file. For example, use root

    $ sudo su
  • Add the extension=vsce_phe_php string in to the php.ini file

    $ echo "extension=vsce_phe_php” >> (PATH_TO_PHP.INI)
  • Copy extension file to the extensions directory.

    • For the Linux/Darwin:
    • Or for the Windows:
     $ cp vsce_phe_php.dll (PATH_TO_EXTENSION_DIR)
  • Then, restart your server or php-fpm service!

Installation example

Our web stack is: Linux, nginx, php7.2-fpm

  • Execute the virgil-test.php to find out your path to php.ini file and path to the extension directory:

  • Then, go to the command line interface (CLI) to specify the paths from the previous step:

  • Reload the page in your browser to see that extension is loaded (IS_EXTENSION_LOADED => TRUE):



This library is released under the 3-clause BSD License.


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